The long-term objective of the Contributors to Augmented Language Competence Project is to characterize and to facilitate the language development of children with mental retardation who encounter significant difficulty acquiring spoken language. In the next five year grant period, this project will extend its research program to pursue two major lines of injury. In the first line of investigation, two studies will examine the contributions of one intrinsic factor, underlying learning strategy, and an extrinsic factor, the representational nature of symbol sets, to the children's symbol achievement patterns. These studies will capitalize on the project's findings to date, on computer-based research tools developed at the Language Research Center (LRC), and on a large subject pool of children with augmented language experience. The expectation is to uncover how these factors influence a child's ability to learn symbols. Further, it will permit the project to refine its augmented language approach to facilitate the language development of a broader range of children with severe mental retardation. The project will also begin a second line of research that has its roots in the project's research findings with school-aged children with mental retardation and in recent findings from the LRC's nonhuman primate research. This second study will use a longitudinal design to examine the effects of early augmented language experience on the communication development of young children with developmental disabilities who are at significant risk for spoken language development. The expectation is that the receptive and expressive communication development of the subjects who receive early augmented language experience will exceed that of children with comparable profiles who do not receive such experience such experience. A further expectation is that this early experience will have a positive influence on parent-child and peer-child communicative interactions, and impact upon educational achievement and subsequent integration into society.